x86/mm: Sync also unmappings in vmalloc_sync_all()

With huge-page ioremap areas the unmappings also need to be synced between
all page-tables. Otherwise it can cause data corruption when a region is
unmapped and later re-used.

Make the vmalloc_sync_one() function ready to sync unmappings and make sure
vmalloc_sync_all() iterates over all page-tables even when an unmapped PMD
is found.

Fixes: 5d72b4fba40ef ('x86, mm: support huge I/O mapping capability I/F')
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20190719184652.11391-3-joro@8bytes.org

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e64173db497015083e1f8ed3fd231614d4a64212..9ceacd1156dbc06c801f86c66e9aa79d104a0cde 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -177,11 +177,12 @@ static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
 
        pmd = pmd_offset(pud, address);
        pmd_k = pmd_offset(pud_k, address);
-       if (!pmd_present(*pmd_k))
-               return NULL;
 
-       if (!pmd_present(*pmd))
+       if (pmd_present(*pmd) != pmd_present(*pmd_k))
                set_pmd(pmd, *pmd_k);
+
+       if (!pmd_present(*pmd_k))
+               return NULL;
        else
                BUG_ON(pmd_pfn(*pmd) != pmd_pfn(*pmd_k));
 
@@ -203,17 +204,13 @@ void vmalloc_sync_all(void)
                spin_lock(&pgd_lock);
                list_for_each_entry(page, &pgd_list, lru) {
                        spinlock_t *pgt_lock;
-                       pmd_t *ret;
 
                        /* the pgt_lock only for Xen */
                        pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
 
                        spin_lock(pgt_lock);
-                       ret = vmalloc_sync_one(page_address(page), address);
+                       vmalloc_sync_one(page_address(page), address);
                        spin_unlock(pgt_lock);
-
-                       if (!ret)
-                               break;
                }
                spin_unlock(&pgd_lock);
        }